INSECTS INJURIOUS TO THE HOP-PLANT. 



275 



yard and infested with lice while they are laying the eggs, 



during fall or -in the spring, before the winged generation 



appears, with some substance which will destroy them, the 



pest may be prevented from getting a start the next season. 



Spraying the trees during the fall 



is best, because a stronger or more 



caustic solution can then be applied 



without danger of injury to the I V.</ 



tree. A winter wash of one pound ^ ' '^■ 



of concentrated lye to two gallons 



of water might be used as a spray / / ' \ 



to advantage in killing a large share 



of the eggs, but should not be applied 



after the buds commence to swell in 



the spring. To lessen the number 



of eggs all wild plum-trees in the Fig. 158. — The Hop 



. . , . 11111 1 Plant-louse, true sex- 



neighbormg woods should be de- ^^.^^ female -enlarged. 



stroyed. As soon as the crop is (After Riley, U. S. 



•^ . ^ Dept. Agr.) 



harvested, the hop-vines should be 



burned or thoroughly sprayed with kerosene emulsion, so 

 as to kill off the males before they have been able to fer- 

 tilize the females. 



For spraying the plum-trees and hop-vines the follow- 

 ing have given excellent satisfaction : 



' 'Kerosene Emulsion. 



Cheap kerosene 8 pints. 



Water 4 '' 



Soap h pound. 



'' Dissolve the soap in the water and add (boiling hot) to 

 the kerosene. Churn the mixture by means of a force- 

 pump and spray-nozzle for 5 or 10 minutes. The emul- 



